This invention relates to an improved stirrer or mixing device and method of mixing which has particular value in mixing metals and metal alloys, particularly those metals and alloys which contain discrete degenerate dendritic primary solid particles and are to be subjected to casting techniques. U.S. Pat. Nos. 3,954,455, and 3,936,298 describe metal and metal alloy compositions which contain discrete degenerate dendritic primary solid particles and disclose the advantages for using such materials in casting techniques; e.g., lower temperatures, longer mold life, etc. In carrying out such casting methods it is necessary that the metal be thoroughly mixed while it is held in the mixing chamber so that when cast, the metal is uniform in composition throughout. Various types of stirrers, including the stirrer disclosed in U.S. Pat. No. 4,116,423 designed especially for metals containing degenerate dendritic solids, have not been totally satisfactory to obtain the necessary thorough mixing. The stirrer of the present invention provides mixing which not only effects agitation in a horizontal plane, but also circulates the molten metal in a vertical direction.